Addison’s disease is a rare condition in which your adrenal glands, small organs that sit on top of your kidneys, stop producing enough of the hormones your body needs to function. It affects roughly 100 to 140 out of every million people in developed countries. The disease develops slowly, often over months, and its early symptoms can look like dozens of other conditions, which makes it easy to miss.
What Your Adrenal Glands Normally Do
The outer layer of each adrenal gland, called the cortex, produces three types of hormones. The most important for understanding Addison’s disease are cortisol and aldosterone. Cortisol helps regulate blood sugar, blood pressure, metabolism, and your body’s response to stress. Aldosterone controls the balance of sodium and potassium in your blood, which in turn controls blood pressure and fluid levels.
In Addison’s disease, the adrenal cortex is gradually destroyed, so production of both cortisol and aldosterone drops. This distinguishes it from other forms of adrenal insufficiency where only cortisol is affected. Losing both hormones at once creates a wider range of symptoms and requires a different treatment approach.
What Causes It
In Western countries, about 80% of cases are caused by an autoimmune reaction. The immune system mistakenly attacks an enzyme in the adrenal cortex, slowly destroying the tissue that produces hormones. This process, called autoimmune adrenalitis, can take years before enough damage accumulates for symptoms to appear.
Tuberculosis accounts for roughly 10% of cases and remains a leading cause in developing countries. Other, rarer causes include fungal infections, cancer that has spread to the adrenal glands, and genetic conditions that affect adrenal function.
Because Addison’s disease is usually autoimmune, it often shows up alongside other autoimmune conditions. People with Addison’s have higher rates of thyroid disease, type 1 diabetes, celiac disease, vitiligo (patches of lost skin color), and pernicious anemia (vitamin B12 deficiency from autoimmune destruction of stomach lining cells). If you’re diagnosed with Addison’s, your doctor will typically screen for these related conditions.
Symptoms and How They Develop
The symptoms are subtle at first and build gradually, which is one reason diagnosis is often delayed. Early signs include persistent fatigue that doesn’t improve with rest, loss of appetite, unintentional weight loss, and nausea. Many people develop intense cravings for salty foods because their body is losing sodium through the kidneys due to low aldosterone.
One hallmark sign is skin darkening, particularly in areas that experience friction or sun exposure: knuckles, elbows, palm creases, armpits, and scars. The inside of the mouth, lips, and gums can also darken. This happens because the brain, sensing low cortisol, ramps up production of a signaling molecule that stimulates pigment-producing cells in the skin. Darkening inside the mouth often appears before changes on the skin become obvious.
Other common symptoms include:
- Low blood pressure that causes dizziness when standing up quickly
- Muscle cramps from electrolyte imbalances
- Low blood sugar, which can cause shakiness, confusion, or irritability
- Mood changes, including irritability or depression
Blood tests in someone with Addison’s typically show low sodium, high potassium, and low blood sugar. These electrolyte shifts are a direct consequence of losing aldosterone.
How Addison’s Disease Is Diagnosed
The most widely used test is the ACTH stimulation test. A synthetic version of the hormone that normally tells your adrenal glands to produce cortisol is injected, and your blood cortisol level is measured 30 to 60 minutes later. Historically, a normal response was a cortisol level of 18 micrograms per deciliter or higher. More recent research using modern, more precise lab methods suggests the cutoff should be closer to 14 to 15 micrograms per deciliter, to avoid falsely diagnosing people who actually have normal adrenal function.
A baseline cortisol level below 2 micrograms per deciliter, taken first thing in the morning, strongly suggests adrenal insufficiency even before stimulation testing. Above that threshold, baseline cortisol alone isn’t reliable enough to confirm or rule out the diagnosis.
Once adrenal insufficiency is confirmed, additional blood work checks for the antibodies that attack the adrenal cortex. If those antibodies are present, the cause is autoimmune. If not, imaging of the adrenal glands or testing for infections like tuberculosis helps identify other causes.
Treatment: Replacing What’s Missing
Addison’s disease is treated by replacing the hormones your adrenal glands can no longer make. This is lifelong therapy, but with proper management most people live full, active lives.
For cortisol replacement, the standard is hydrocortisone taken in divided doses throughout the day. Guidelines recommend 15 to 25 mg daily, with 20 mg as a typical midpoint. Some researchers believe many patients do well on lower doses, closer to 15 mg per day, which may reduce long-term side effects of excess cortisol replacement like bone thinning and weight gain. Finding the right dose is individual and usually involves adjusting based on how you feel, your energy levels, and periodic lab work.
For aldosterone replacement, a synthetic mineralocorticoid is taken once daily. The dose is adjusted based on blood pressure readings, sodium and potassium levels, and a blood marker called plasma renin activity.
Sick Day Rules and Stress Dosing
One of the most important things to understand about living with Addison’s disease is that your body can no longer ramp up cortisol production when it’s under stress. A healthy person’s adrenal glands automatically release extra cortisol during illness, injury, or surgery. Yours can’t, so you need to adjust your medication manually.
The general guidelines break down into two rules. The first applies to moderate stress: fever, an illness that keeps you in bed, an infection requiring antibiotics, or a minor procedure like dental work. In these situations, you double your usual oral dose for the duration of the illness, up to about seven days. The second rule covers severe situations: persistent vomiting (where you can’t keep pills down), major trauma, fasting for a medical procedure, or surgery. These require an emergency injection of hydrocortisone, which is why people with Addison’s disease carry an injectable kit with them.
Prolonged intense exercise or severe psychological stress can also warrant an extra dose. Both you and the people close to you should know the sick day rules, recognize the warning signs of a crisis, and know how to administer the emergency injection.
Adrenal Crisis: The Serious Emergency
An adrenal crisis happens when your cortisol levels drop dangerously low, usually triggered by an illness, injury, or missed medication. Symptoms escalate quickly: severe weakness, confusion, sharp abdominal or leg pain, vomiting, very low blood pressure, and loss of consciousness. Without treatment, it can be fatal.
Emergency treatment involves intravenous cortisol injections and large volumes of saline solution with added sugar to correct dehydration, low sodium, and low blood sugar simultaneously. Recovery is usually rapid once treatment begins, but the crisis itself is preventable in most cases by following stress dosing rules and seeking care early during illness.
People with Addison’s disease are advised to wear a medical alert bracelet or carry an identification card so that emergency responders know to administer cortisol if the person is unconscious or unable to communicate.